Ethanol-Free GoGas outgassing?

[Bill B.]

Does anyone have experience with 93 PON Ethanol-Free gasoline from GoGas stations?

I obtained a tank-full for the first time but am experiencing lots of fuel odor in the closed garage.

I also notice the gas tank retaining lots of vapor pressure. Every time I slowly open the tank cap to release that pressure and place it back on, I return a day later to find the same amount of pressure build-up again.

While it may not contain Ethanol, it has some other chemical additive that appears to "outgas" constantly and really stinks up the garage! The smell reminds me of Toluene.

When working on the underside of my vehicle, the vapor appears to be heavier than air, as it is really strong just inches off the floor. (Yes, I have been all over the vehicle to check for a just occurred coincidence fuel weepage, but none found)

While I love the prospect of Ethanol-free, I (and my wife) find the outgassing smell unacceptable with this particular product (eastern North Carolina) and even a potential safety hazard, not only from having to breathe it in while working close to the floor under the vehicle, but my natural gas hot water heater is located in an adjacent room open to the garage. (it is raised off the floor by 17", however ...)

If anyone has experienced similar situations or can share some technical knowledge on this, we'd appreciate it. Thanks!

[Ray G.]

Re: Ethanol-Free GoGas outgassing?

Hello;
Have not had experience with the fuel. But suggest you use a venting gas cap.
my .02
Ray

[Duke W.]

Re: Ethanol-Free GoGas outgassing?

Achieving 93 PON (which is equivalent to the old 97-98 RON in terms of detonation resistance) without ethanol requires some very high octane components including from the aromatics family of which I believe toluene is a member. It sounds to me like this blend may be exceeding EPA vapor pressure requirements. You should contact the blender and ask them for the Reid vapor pressure and you can probably find the EPA winter and summer requirements on line.

I believe aromatics are banned from California gasoline blends because they are considered carcinogenic, and that's probably why our highest available E10 octane is 91 PON. I also believe California has its own summer and winter Reid vapor pressure requirements that differ from EPA requirements that most states use.

Duke

[Bill B.]

Re: Ethanol-Free GoGas outgassing?

Thanks Duke. Will investigate, but sounds like it is back to the E10 for me.

B

[James G.]

Re: Ethanol-Free GoGas outgassing?

I had issues with attempting to run either 87 non ethanol alone (retarded timing) or ethanol laced 93 which I found boiling in the fuel bowls.
2 years ago I switched to a mix of approx 4 gal of Sunoco 110 race and then filling the tank with 87 non-ethanol - with this mix
I can run an aggressive advance curve without detonation and haven't had fuel boiling in the bowls.
Spitballing I guess that the octane is 92-94 range.

[Mark L.]

Re: Ethanol-Free GoGas outgassing?

I've used the 100 LL aviation gas and don't remember getting the odor you describe. I'd guess the distillation curve for Av gas is significantly different than the vehicle gas.

[James G.]

Re: Ethanol-Free GoGas outgassing?

One of my customers runs 100LL in his fleet of vintage HP cars.
IIRC approx 2 years ago he said the price on a drum worked out to $3.72/gal.
If you dont mind revealing, what are they charging for 100LL now?
FWIW Sunoco 110 is $10.99/gal local in South Carolina.

[Mike M.]

Re: Ethanol-Free GoGas outgassing?

i paid about $6 per gal of av gas about 4 months ago. expect its higher now. no problems with fumes and the FI's love it. mike

[Dan A.]

Re: Ethanol-Free GoGas outgassing?

I run 91 octane ethanol free in my 72 LT-1 and as expected it runs fine. I haven’t noticed any unusual odors but the fuel boiling issue I had with the ethanol laced fuels is gone.

[Mark F.]

Re: Ethanol-Free GoGas outgassing?

There are two problems here as I see it:

1. Odor (very subjective and VERY difficult to quantify) and
2. Vapor Pressures (VPs) of gasoline components.

The VPs are easy - ask your supplier for a Safety Data Sheet (SDS) (they used to be called Material SDSs) for the gas your are buying. Your local vendor may not (probably won't) have one, but whomever they are buying their gas from MUST have one by law. So, ask for it to be supplied to you (from whatever source).

The pressure against the inside of the gas cap will be mostly determined by the highest VP component of the gasoline (unless it is a very small % of the mixture). Usually, the lower the molecular weight of an aromatic; the higher the VP...I'm sure there are exceptions.

If you provide all of those components for the gas you are buying, I may be able to look up "Odor Thresholds" for the substances in the gas mix.

The most volatile compound (the one with the highest VP) is not always the most "odorous" component. Odor thresholds are notoriously difficult to compare.

You and your wife are apparently smelling something "unpleasant". I once worked with a Chemist who thought carbon disulfide (CS₂) smelled "good" - and did not like the smell of benzene. My reaction to both of the chemicals was the exact opposite. CS₂ smells like "dead rotting fish" to me and benzene is kind-of-a-sweet smell. Different strokes for different folks...

[Larry E.]

Re: Ethanol-Free GoGas outgassing?

FWIW> Prices for AvGas & Non-Ethanol Gas in North Central Illinois

100LL>$5.95/Gallon
Jet>$6/Gallon

FS

Ethanol Free Premium @Regular Gas Pumps>$4.799/Gal (eg.Used in Trimmers and Grass Cutting Lawn Tractors and Scooters)

[James G.]

Re: Ethanol-Free GoGas outgassing?

Sunoco 110 is 5.6 https://www.sunocoracefuels.com/fuel/standard
Exxon Mobile 100LL 5.5-7 https://www.exxonmobil.com/en/aviati...ts/avgas-100ll
EPA website - "Depending on the state and month, gasoline RVP may not exceed 9.0 psi or 7.8 psi." https://www.epa.gov/gasoline-standar...vapor-pressure